Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.io.*;
import java.util.*;
import java.lang.*;
import java.awt.*;
import java.awt.geom.*;
import java.math.*;
import java.text.*;
import java.math.BigInteger.*;
import java.util.Arrays; 

public class   wantyouwantyou
{
  BufferedReader in;
  StringTokenizer as;
  int nums[][],nums2[],nums3[],nums4[],nums5[];
  ArrayList < String >  ar  = new ArrayList < String > ();
  boolean con1 = false;
  public static void main (String[] args)
  {
    new wantyouwantyou  ();
  }
  
  public wantyouwantyou  ()
  {
    try
    {
      
      in = new BufferedReader (new InputStreamReader (System.in));
      int a = nextInt();
      int b  = nextInt();
      nums = new int [a][b];
      for(int x = 0;x<a;x++)
      {
        for(int x1 = 0;x1<b;x1++)
        {
          nums[x][x1] = nextInt();
        }
      }
      int min = 10000000;
      for(int xx = 0;xx<=500;xx++)
      {
        int temp = 0;
        
        nums3 = new int [b];
        
        boolean con = true;
        for(int x1 = 0;x1<b;x1++)
        {
          if(nums[0][x1] < xx)
          {
            con = false;
            break;
            
          }
          else
          {
            nums3[x1] = nums[0][x1] - xx;
            temp += nums3[x1];
          }
        }
        if(con)
        {
          nums2 = new int [a];
          nums2[0] = xx;
          temp += xx;
          for(int x = 1;x<a;x++)
          {
            if(nums[x][0] < nums3[0])
            {
              con = false;
              break;
            }
            else
            {
              nums2[x] = nums[x][0] - nums3[0];
              temp += nums2[x];
            }
          }
          if(con && temp < min)
          {
            for(int x = 0;x<a;x++)
            {
              for(int x1 = 0;x1<b;x1++)
              {
                if(nums2[x] + nums3[x1] != nums[x][x1])
                {
                  con = false;
                  break;
                }
              }
            }
            if(con)
            {
              con1 = true;
              min = temp;
              nums4 = nums2;
              nums5 = nums3;
       
            }
          }
        }
        
        
      }
      if(con1)
      {
        System.out.println(min);
        for(int x = 0;x<a;x++)
        {
          while(nums4[x] != 0)
          {
           System.out.println("row " + (x+1));
            nums4[x]--;
          }
        }
        for(int x = 0;x<b;x++)
        {
          while(nums5[x] != 0)
          {
            System.out.println("col " + (x+1));
            nums5[x]--;
          }
        }
      }
      else
      {
        System.out.println(-1);
      }
    }
    catch(IOException e)
    {
      
    }
  }
  
  
  
  
  
  
  
  String next () throws IOException
  {
    while (as == null || !as.hasMoreTokens ())
    {
      as = new StringTokenizer (in.readLine ().trim ());
    }
    
    
    return as.nextToken ();
  }
  
  
  
  long nextLong () throws IOException
  {
    return Long.parseLong (next ());
  }
  
  
  int nextInt () throws IOException
  {
    return Integer.parseInt (next ());
  }
  
  
  double nextDouble () throws IOException
  {
    return Double.parseDouble (next ());
  }
  
  
  String nextLine () throws IOException
  {
    return in.readLine ().trim ();
  }
}